CN116840775A - Weak signal extraction method for known strong signal scene - Google Patents
Weak signal extraction method for known strong signal scene Download PDFInfo
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- CN116840775A CN116840775A CN202310787469.3A CN202310787469A CN116840775A CN 116840775 A CN116840775 A CN 116840775A CN 202310787469 A CN202310787469 A CN 202310787469A CN 116840775 A CN116840775 A CN 116840775A
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- 238000005070 sampling Methods 0.000 claims description 15
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- 230000009286 beneficial effect Effects 0.000 description 3
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S3/00—Direction-finders for determining the direction from which infrasonic, sonic, ultrasonic, or electromagnetic waves, or particle emission, not having a directional significance, are being received
- G01S3/02—Direction-finders for determining the direction from which infrasonic, sonic, ultrasonic, or electromagnetic waves, or particle emission, not having a directional significance, are being received using radio waves
- G01S3/14—Systems for determining direction or deviation from predetermined direction
Abstract
The invention relates to a weak signal extraction method of a known strong signal scene, belonging to the field of radio direction finding. Under the co-location condition of the antenna array and the radar, the invention determines the signal matrix received by the acquired antenna array; then determining a sample autocorrelation matrix of the signal received by the antenna array, and determining a projection autocorrelation matrix by a direction vector of the incoming wave direction of the known strong signal; then, singular value decomposition is carried out on the projection autocorrelation matrix, and a singular vector corresponding to the maximum singular value is determined to be a weight vector of the spatial filter; and finally, determining weak signals with known strong signal incoming wave directions by the weight vectors of the spatial filter. The invention realizes the extraction of the weak signals with unknown incoming wave directions in the antenna array signals.
Description
Technical Field
The invention belongs to the field of radio direction finding, and particularly relates to a weak signal extraction method for a known strong signal scene.
Background
The radio signal received by the antenna array can be used for not only direction finding of a radiation source for radiating the radio signal, but also spatial filtering of a plurality of signals which are aliased together in time domain and frequency domain, and has important significance in the aspects of interference source monitoring, electromagnetic spectrum multiplexing, multi-signal resolution and the like of electronic information equipment such as communication, radar and the like.
Radars working in complex target environments and electromagnetic spectrum environments are often affected by various interference sources, and as pulse signals radiated by the interference sources and pulse signals radiated by the radars are aliased together in time domains and frequency domains, the false alarm probability, detection probability, direction finding and ranging accuracy and other target detection performances of the radars are deteriorated. The method has the advantages that the spatial filtering is carried out on the radio signals received by the antenna array, the pulse signal waveform radiated by the interference source can be separated, and important basis is provided for analyzing and inhibiting the influence of the interference source on the radar target detection performance.
There are many methods for spatial filtering of radio signals received by an antenna array, including conventional beam forming filtering methods, minimum variance distortion-free response filtering methods, and the like. The method mainly comprises the steps of performing spatial filtering processing on signals received by an antenna array under the condition of given incoming wave direction, and extracting the signals in the incoming wave direction. However, in the case where the antenna array is co-located with the radar, i.e. when the antenna array is operated in the vicinity of the radar, the signals received by the antenna array contain both the pulsed signals of co-located radar radiation and the signals of the interference source radiation, wherein the direction of the incoming wave of the pulsed signals of co-located radar radiation is known and the pulsed signals of the interference source radiation is unknown. Therefore, when the incoming wave direction of the pulse signal radiated from the co-located radar is known, it is necessary to perform spatial filtering processing on the signal received from the antenna array, and extract a weak signal whose wave direction is unknown.
Because the antenna array and the co-located radar work in the same time domain and frequency domain and are influenced by the far-near effect, the signal amplitude of the radiation of the remote interference source is far smaller than the pulse signal amplitude of the radiation of the near co-located radar in the signals received by the antenna array. Therefore, it is necessary to perform spatial filtering processing on the signals received by the antenna array to extract weak signals with unknown wave directions when the pulse signal amplitude of the co-located radar radiation is far greater than the signal amplitude of the interference source radiation.
Disclosure of Invention
First, the technical problem to be solved
The invention aims to provide a weak signal extraction method for a known strong signal scene, so as to solve the problem that weak signals are difficult to extract from signals received from an antenna array because pulse signals radiated by a radar are far stronger than signals radiated by an interference source and are aliased together in time domain and frequency domain under the co-location condition of the antenna array and the radar.
(II) technical scheme
In order to solve the above technical problems, the present invention provides a weak signal extraction method for a known strong signal scene, the method comprising the following steps:
s1, setting the number of antennas forming an antenna array, sampling period, sampling number of signals according to the sampling period, known incoming wave direction of radar pulse signals and direction vectors corresponding to the incoming wave direction of the known radar pulse signals;
s2, under the co-location condition of the antenna array and the radar, determining a signal matrix received by the acquired antenna array;
s3, determining a sample autocorrelation matrix of signals received by the antenna array, and determining a projection autocorrelation matrix by a direction vector of the incoming wave direction of the known strong signals;
s4, carrying out singular value decomposition on the projection autocorrelation matrix, and determining a singular vector corresponding to the maximum singular value as a weight vector of the spatial filter;
s5, determining weak signals with known strong signal incoming wave directions by the weight vectors of the spatial filter.
(III) beneficial effects
The invention provides a weak signal extraction method of a known strong signal scene, which has the beneficial effects that: the weak signal extraction method for the known strong signal scene can design an optimal spatial filter for extracting weak signals by utilizing the known incoming wave direction of the strong signals under the condition that the pulse signals radiated by the radar are far stronger than signals radiated by the interference source and are mixed together in the time domain and the frequency domain, so as to realize the purpose of extracting the weak signals with unknown incoming wave direction in the antenna array signals.
Detailed Description
To make the objects, contents and advantages of the present invention more apparent, the following detailed description of the present invention will be given with reference to examples.
Aiming at the problem that weak signals are difficult to extract from signals received by an antenna array due to the fact that pulse signals radiated by the radar are far stronger than signals radiated by an interference source and are mixed together in time domain and frequency domain under the co-location condition of the antenna array and the radar, the invention designs an optimal airspace filter for extracting the weak signals by utilizing the known incoming wave direction of the strong signals, and achieves the purpose of extracting the weak signals with unknown incoming wave direction in the signals of the antenna array.
The technical scheme of the invention is as follows:
a weak signal extraction method of a known strong signal scene, the method comprising the steps of:
s1, setting the number of antennas forming an antenna array, sampling period, sampling number of signals according to the sampling period, known incoming wave direction of radar pulse signals and direction vectors corresponding to the incoming wave direction of the known radar pulse signals;
s2, under the co-location condition of the antenna array and the radar, determining a signal matrix received by the acquired antenna array;
s3, determining a sample autocorrelation matrix of signals received by the antenna array, and determining a projection autocorrelation matrix by a direction vector of the incoming wave direction of the known strong signals;
s4, carrying out singular value decomposition on the projection autocorrelation matrix, and determining a singular vector corresponding to the maximum singular value as a weight vector of the spatial filter;
s5, determining weak signals with known strong signal incoming wave directions by the weight vectors of the spatial filter.
Specifically, the method specifically comprises the following steps:
s1, setting the number M of antennas forming an antenna array and a sampling period, wherein the antenna array collects the sample number L of signals and the incoming wave direction theta of known strong signals according to the sampling period 1 A direction vector a (θ 1 )；
S2, under the co-location condition of the antenna array and the radar, determining a signal matrix received by the acquired antenna array as an M multiplied by L matrix X;
s3, determining a sample autocorrelation matrix R of signals received by the antenna array 1 The method comprises the following steps:
R 1 ＝XX H
wherein () H For conjugate transposition of the matrix and determining the projection autocorrelation matrix R from a set of direction vectors of known incoming wave direction 2 The method comprises the following steps:
wherein I is an identity matrix;
s4, a projection autocorrelation matrix R 2 Singular value decomposition is carried out, and a singular vector corresponding to the maximum singular value is determined as a weight vector w of the spatial filter;
s5, finally, determining a weak signal with a known strong signal incoming wave direction as S by a weight vector w of a spatial filter:
s＝w H X
example 1:
the utility of the present invention is analyzed in connection with the following examples.
In this example, the number of antennas constituting the antenna array is set to m=8; when the antenna array and the radar are co-located, the incoming wave direction of the pulse signal radiated by the radar is 13.81 degrees with respect to the antenna array, and the 1 st to 8 th elements of the direction vector corresponding to the direction are respectively:
the pulse signal radiated by the radar is a linear frequency modulation signal, the bandwidth is 5MHz, and the pulse width is 10us; the pulse signal radiated by the interference source is also a linear frequency modulation signal, the bandwidth is 5MHz, and the pulse width is 10us. In the signals received by the antenna array, the signal to noise ratio of the pulse signals of the radar radiation is 18dB; the incoming wave direction of the signal radiated by the interference source is 27.91 degrees, and the signal-to-noise ratio is 0dB. There is 84% overlap in time domain with the pulse signal of the radar radiation. It can be seen that when the signal arrives at the antenna array, the pulse signal radiated by the interference source completely overlaps with the pulse signal radiated by the radar in the frequency domain, and the pulse signal radiated by the radar is 18dB stronger than the signal power radiated by the interference source.
And acquiring signals according to the sampling period of 0.1us, wherein the sample number L=250, and acquiring signals received by all antennas of the antenna array under the co-location condition of the antenna array and the radar, wherein the signals are 8×256-order matrixes. By using a conventional wave beam forming filtering method and a minimum variance undistorted response filtering method, a spatial filter can be designed according to the known incoming wave direction of the pulse signal of radar radiation, the pulse signal of radar radiation is extracted, then the extracted pulse signal of radar radiation is subtracted from the signal received by an antenna array, and a weak signal with unknown incoming wave direction is obtained, wherein the signal-to-noise ratio is-3.67 dB and-6.25 dB respectively, and the error is larger. The method of the invention directly extracts the signal radiated by the interference source, has a signal-to-noise ratio of 5.68dB and lower error, and realizes the purpose of extracting the weak signal with unknown incoming wave direction in the antenna array signal.
The beneficial effects of the invention are as follows: the weak signal extraction method for the known strong signal scene can design an optimal spatial filter for extracting weak signals by utilizing the known incoming wave direction of the strong signals under the condition that the pulse signals radiated by the radar are far stronger than signals radiated by the interference source and are mixed together in the time domain and the frequency domain, so as to realize the purpose of extracting the weak signals with unknown incoming wave direction in the antenna array signals.
The foregoing is merely a preferred embodiment of the present invention, and it should be noted that modifications and variations could be made by those skilled in the art without departing from the technical principles of the present invention, and such modifications and variations should also be regarded as being within the scope of the invention.
Claims (10)
1. A method for extracting a weak signal from a scene of a known strong signal, the method comprising the steps of:
s1, setting the number of antennas forming an antenna array, sampling period, sampling number of signals according to the sampling period, known incoming wave direction of radar pulse signals and direction vectors corresponding to the incoming wave direction of the known radar pulse signals;
s2, under the co-location condition of the antenna array and the radar, determining a signal matrix received by the acquired antenna array;
s3, determining a sample autocorrelation matrix of signals received by the antenna array, and determining a projection autocorrelation matrix by a direction vector of the incoming wave direction of the known strong signals;
s4, carrying out singular value decomposition on the projection autocorrelation matrix, and determining a singular vector corresponding to the maximum singular value as a weight vector of the spatial filter;
s5, determining weak signals with known strong signal incoming wave directions by the weight vectors of the spatial filter.
2. The method for extracting a weak signal from a known strong signal scene according to claim 1, wherein the step S1 specifically comprises:
setting the number M of antennas forming an antenna array and a sampling period, wherein the antenna array collects the sample number L of signals and the incoming wave direction theta of known radar pulse signals according to the sampling period 1 A direction vector a (θ) corresponding to the direction of the incoming wave of the known radar pulse signal 1 )。
3. A weak signal extraction method for a known strong signal scenario according to claim 2, characterized in that the number of antennas M = 8 constituting the antenna array is set.
4. A weak signal extraction method for a known strong signal scene according to claim 2, characterized in that the signal is acquired with a sampling period of 0.1us, the number of samples L = 250.
5. The method for extracting a weak signal from a known strong signal scene according to claim 2, wherein the incoming wave direction of the known radar pulse signal is a strong signal incoming wave direction.
6. A weak signal extraction method for a known strong signal scene according to any of claims 2-5, wherein said step S2 specifically comprises: and under the co-location condition of the antenna array and the radar, determining the signal matrix received by the acquired antenna array as an M multiplied by L matrix X.
7. The method for extracting weak signals from a known strong signal scenario as claimed in claim 6, wherein determining the sample autocorrelation matrix of the signal received by the antenna array in step S3 specifically comprises:
determining a sample autocorrelation matrix R of a signal received by an antenna array 1 The method comprises the following steps:
R 1 ＝XX H
wherein () H Is the conjugate transpose of the matrix.
8. The method for extracting a weak signal from a scene of a known strong signal according to claim 7, wherein determining the projection autocorrelation matrix from the direction vector of the incoming wave direction of the known strong signal in step S3 specifically comprises:
determining a projection autocorrelation matrix R from a set of direction vectors of known incoming wave directions 2 The method comprises the following steps:
wherein I is an identity matrix.
9. Such asThe method for extracting a weak signal from a known strong signal scene as set forth in claim 8, wherein the step S4 specifically includes: for projection autocorrelation matrix R 2 And (3) performing singular value decomposition, and determining a singular vector corresponding to the maximum singular value as a weight vector w of the spatial filter.
10. The method for extracting a weak signal from a known strong signal scene according to claim 9, wherein the step S5 specifically comprises: the weight vector w of the spatial filter determines that the weak signal with the known strong signal incoming wave direction is s:
s＝w H X。
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Citations (8)
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| JP2005121581A (en) * | 2003-10-20 | 2005-05-12 | Mitsubishi Electric Corp | Radar device |
| JP2006145251A (en) * | 2004-11-16 | 2006-06-08 | Denso Corp | Radio wave arrival direction prediction system |
| CN103217670A (en) * | 2013-03-29 | 2013-07-24 | 电子科技大学 | Outer radiation source weak signal detection method based on PCA (principal component analysis) |
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| CN106199547A (en) * | 2016-06-30 | 2016-12-07 | 西安电子科技大学 | Weak target detection method at a slow speed based on external illuminators-based radar |
| CN110161489A (en) * | 2019-05-21 | 2019-08-23 | 西安电子科技大学 | A kind of strong and weak signals direction-finding method based on pseudo- frame |
| CN114679227A (en) * | 2022-03-25 | 2022-06-28 | 电子科技大学 | Space frequency domain correction method for direction finding error |
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- 2023-06-30 CN CN202310787469.3A patent/CN116840775B/en active Active
Patent Citations (8)
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| JP2005121581A (en) * | 2003-10-20 | 2005-05-12 | Mitsubishi Electric Corp | Radar device |
| JP2006145251A (en) * | 2004-11-16 | 2006-06-08 | Denso Corp | Radio wave arrival direction prediction system |
| CN103217670A (en) * | 2013-03-29 | 2013-07-24 | 电子科技大学 | Outer radiation source weak signal detection method based on PCA (principal component analysis) |
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| CN103760518A (en) * | 2013-10-29 | 2014-04-30 | 电子科技大学 | Measuring method for antenna array direction vectors of a plurality of signals with unknown directions |
| CN106199547A (en) * | 2016-06-30 | 2016-12-07 | 西安电子科技大学 | Weak target detection method at a slow speed based on external illuminators-based radar |
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